Pump



vNov. 29, 1966 w. G. MCKENZIE PUMP Filed Jan. 13, 1965 United States Patent 3,288,072 PUNIP William G. McKenzie, Racine, Wis., assignor to Walker Manufacturing Company, Racine, Wis., a corporation of Wisconsin Filed Jan. 13, 1965, Ser. No. 425,126 Claims. (Cl. 103-43) This invention relates generally to fluid pumping means and, more particularly, to a pumping apparatus for providing periodic surges of fluid in a fluid metering system.

It is a general object of the present invention to provide a fluid pumping device which supplies fluid to an associated fluid metering system in successive pulses surges.

It is another object of the present invention to provide a fluid pumping device of the above character which has very few moving components and therefore has a long service life.

It is still another object of the present invention to provide a fluid pumping device of the above character that is simple in construction and operation, and which is therefore economical to commercially produce.

It is yet another object of the present invention to provide a fluid pumping device of the above character which is of a rugged and durable construction and is energized by readily available electric current.

In accordance with the principles of the present invention, the foregoing and other related objects and advantages are attained through the provision of a novel pumping device which includes a thermal-motor actuated piston assembly having a built-in fluid accumulator chamber. Upon energization of the motor, the accumulator chamber stores a predetermined quantity of fluid until a preselected fluid pressure is obtained within the assembly, at which time an associated valve means will rapidly open to permit the fluid under pressure within the accumulator chamber to suddenly surge into an associated fluid metering system.

A more complete understanding of the present invention and other objects and features thereof will be obtained from the following detailed description taken in conjunction with the accompanying drawing, wherein:

FIGURE 1 is a longitudinal cross-sectional view of the pumping device embodying the present invention;

FIGURE 2 is an end elevational view of the pumping device illustrated in FIGURE 1; and

FIGURE 3 is a top elevational view of the pumping device illustrated in FIGURE 1.

Referring now to FIGURE 1 of the drawing, a fluid pumping device 10, in accordance with a preferred embodiment of the present invention, is shown operatively secured to a generally L-shaped mounting bracket 12 which comprises a horizontally extending lower section 14 and an upwardly or vertically extending end section 16. Rigidly secured to the right end of the mounting brackets lower section 14, as by suitable machine screws 18, is a piston housing that is formed with a central annual bore which defines a fluid pumping chamber, generally designated 22. Reciprocally mounted within the chamber 22 is a hollow elongated cylindrical piston member 24 whose left end is closed by an end section 25. A suitable O-ring sealing member 26 is compressed be- Patented Nov. 29, 1966 "ice tween an annular recess 27 formed around the inner periphery of the chamber 22, and the outer periphery of the piston member 24, which sealing member 26 serves to prevent fluid leakage between the left end of the chamber 22 and the outer periphery of the piston 24. The outer periphery of the left end of the piston member 24 projects radially outwardly, as seen at 28, and defines an annular shoulder 30 against which is abutted the left end of a helical return spring 32 that extends coaxially around the right end of the piston member 24. The opposite (right) end of the return spring 32 abuts against a radially outwardly extending shoulder section 34 formed around the left end of the piston housing 20, whereby the return spring 32 is maintained under a state of slight compression and thus normally resists movement of the piston member 24 into the pumping chamber 22.

Formed in the right end of the piston housing 20 is a valve bore 36 which extends coaxially of the accumulator chamber 22 and is communicable therewith through a discharge orifice 38 that is defined by an annular valve seat section 40 formed in the housing 20 between the bore 36 and chamber 22. The orifice 38 is selectively closed by a spherical ball valve member 42 which is resiliently urged into engagement with an O-ring sealing member 44 located adjacent the valve seat section 40 by a helical coil spring 46. The outer (right) end of the spring 46 abuts against a suitable plug 48 that is threaded within and closes the outer (right) end of the bore 36, a suitable gasket 50 being interposed between the end of the housing 20 and the plug 48 to assure that there is no fluid leakage therebetween. As best seen in FIGURE 2, a radially inwardly extending fluid passage 52 is formed in the housing 20 and is communicable at its inner end with the interior of the bore 36. Threadedly mounted within an enlarged diameter outer section 54 of the bore 52 is a suitable fluid fitting 56 which is adapted to communicate fluid from the bore 52 to a suitable outlet conduit 58 that is secured to the fitting 56 and serves to transmit fluid pumped by the device 10 to an associated fluid metering or dispensing mechanism, as will be described.

Fluid is communicated into the interior of the pumping chamber 22 through a suitable inlet conduit 60 and a combination fluid inlet fitting and valve housing, generally designated 62, that is mounted within a suitable bore 64 formed in the top of the housing 20 and communicable with the interior of the pumping chamber 22. The fitting 62 is formed with a central bore 66 which is communicable at one end with a reduced diameter nipple section 68 upon which the inlet conduit 60 is mounted. Disposed within the bore 66 is a spherical valve member 70 which is resiliently seated against a suitable O-ring sealing member 72 by means of a helical coil spring 74. It will be seen that the valve member 70 is arranged such that fluid may flow through the fitting 62 into the interior of the pumping chamber 22, but is prevented from flowing out of the chamber 22 through the fitting 62 and conduit 60. In a similar manner, the aforementioned valve member 42 is arranged within the outlet bore 36 such that fluid may easily flow out of the chamber 22 through the bore 36; however, fluid is prevented from flowing into the chamber 22 through the bore 36 by virtue of the valve 42 being resiliently seated against the sealing member 44 by the spring 46.

As best seen in FIGURE 1, the piston member 24 is formed with a central cylindrical bore which defines a fluid accumulator chamber 76. Reciprocally mounted within the chamber 76 is an accumulator piston assembly 78 comprising an annular piston member 80 upon which is mounted an annular sealing member 82 that is generally cup-shaped in transverse section. The piston assembly 78 is resiliently urged toward the right end of the piston member 24 by means of a coil spring 84 that extends coaxially within the chamber 76 and is supported at its left end within an annular recess 86 formed in the end section 25 of the piston member 24. The right end of the spring 84 is supported within a cup-shaped recess 88 formed on the left side of the piston member 80. The coil spring 84 resiliently urges the piston assembly 78 into engagement with a disc-shaped probe support member 90 which extends transversely across and is rigidly secured within the right end of the chamber 76 by means of a conventional snap-ring or the like 92. The member 90 is formed with a central probe 94 which projects toward the right end of the housing 20 and is coaxially aligned with the discharge orifice 38 communicating the pumping chamber 22 with the bore 36. The support member 90 is also formed with a plurality of circumferentially spaced openings or apertures, generally designated 96, which communicate the interior of the pumping chamber 22 with the accumulator chamber 76, as will be described.

Actuation of the pumping device of the present invention is achieved through the use of a thermal energized motor, generally designated 98, that is disposed within an within an elongated cylindrical housing 200 which extends coaxially through an annular opening 102 formed in the upwardly extending section 16 of the mounting bracket 12. The housing 100 also extends through a central opening 104 formed in a flat disc-shaped retainer 106 which is resiliently urged into engagement with a radially outwardly extending shoulder section 108 formed on the right end of the housing 100 by a helical safety spring 110 which is compressed between the upwardly extending section 16 of the bracket 12 and an annular recess 112 formed on the left side of the retainer 106 circumjacent the opening 104. As best seen in FIGURE 3, a pair of generally L-shaped retainer clips 114 and 116 are secured at their right ends to the opposite sides of the retainer 106 by suitable screws 118 and 120, respectively, which clips 114 and 116 have their opposite (left) ends bent inwardly or toward one another and engaged with the outer or left side of the upwardly extending section 16 of the mounting bracket 12, whereby the retainer 106 and motor housing 100 are free to move toward the bracket section 16 but are prevented from moving more than a predetermined distance away from the section 16 by the brackets 114 and 116.

The thermal motor 98 is preferably of the wax pellet type and includes a suitable electric heating element (not shown) which is adapted to be energized by connecting a suitable source of electric current, such as house current or the like, with a pair of lead lines 122 which are communicable with the heating element. Upon energization of the heating element, a wax pellet that is located within the housing 100 adjacent the element expands a predetermined amount, thereby biasing a piston rod 124, which is engageable with the end section 25 of the piston member 24, outwardly to effect actuation of the pumping device 10.

Secured to the top of the retainer 106, as by welding or the like, is an L-shaped actuating switch support bracket 126, to which an actuating switch 128 is rigidly attached by suitable bolts 130 and nuts 132. The switch 128, which is of a conventional toggle type and connected with the aforementioned source of electric current used to energize the thermal motor 98, is adapted to be actu- 'ated upon engagement by a suitable tripping means which is provided herein by a bolt 134 and nut 136 that are adjustably secured to the upper end of a Z-shaped bracket 138 rigidly secured, as by welding, to the upper end of the mounting bracket section 16. The side of the actuating switch 128 opposite that which is engageable with the tri ping means provided by the bolt 134 is engageable with another bolt 140 which is threaded within the upper end of a bracket 142 and secured thereto by a locknut 144, the bracket 142 being secured at its lower end to the top of the left end of the piston member 24,

as by welding or the like. Engagement of the bolt 140 with the switch 128 serves to reset the actuating mechanism within the switch 128 that is tripped upon engagement of the switch 128 with the bolt 134, as will hereinafter be described.

Assuming that the lead lines 122 are connected to a suitable source of electric current, and that the fluid inlet and outlet conduits and 58 are connected to an appropriate source of fluid and to an associated fluid meter of the motor 98, the piston rod 124 will be biased out wardly or away from the end of the motor housing 100, thereby urging the piston member 24 toward the right end of the pumping chamber 22. As the piston member 24 is thus moved, the fluid pressure within the pumping chamber 22 will begin to increase, the reason for this being that the valve member prevents fluid within the chamber 22 from being forced back into the fluid inlet,

conduit 60 and the valve member 42 prevents fluid within the chamber 22 from passing into the bore 36 until a predetermined fluid pressure is obtained within the chamber 22. loaded such that a fluid pressure of approximately It will be noted that the spring 46 is prep.s.i. is required to unseat the ball valve 42. Also, it

will be noted that the spring 84 is preloaded such that when the fluid pressure within the chamber 22 reaches approximately 60 p.s.i., the piston assembly 78 will move toward the left end of the piston member 24 against the resistance of the spring 84. Accordingly, as the piston member 24 moves toward the right of the pumping chamber 22, and the fluid pressure within the chamber 22 increases above 60 p.s.i., the piston assembly '78 will move toward the left end of the accumulator chamber 76, until such time as the probe 94 projecting from the right end of the piston member 24 engages and unseats the valve member 42, whereby the fluid pressure within the pumping chamber 22 is suddenly relieved. When the pressure within the chamber 22 drops below 60 p.s.i., the spring 84 will move the piston assembly 78 rapidly toward the right end of the piston member 24, causing the fluid within the accumulator chamber 76 to surge through the discharge orifice 38, the bore 36 and outlet passage 52, from where this fluid is communicated through the fluid outlet conduit 58 to the associated fluid metering or dispensing device.

The forward movement of the piston member 24 is terminated when the right end thereof engages the right end of the pumping chamber 22; however, the thermal motor 98 continues to operate, whereby both the motor 98 and the motor housing 100 are biased toward the left or, in other words, in the opposite direction from the aforediscussed forward movement of the piston member 24. As the motor housing 100 moves toward the left, the spring retainer 106 also moves toward the left against the resistance of the safety spring until the actuating switch 128 engages and is actuated by the bolt 134 threaded in the upper end of the bracket 138. When the switch 128 is thus actuated, the electric circuit communicating current to the thermal motor 98 is broken, at which time the heating element within the housing to communicate said pumping chamber with said fluid outlet passage,

said piston means movable in one direction within said pumping chamber whereby the fluid pressure within said pumping chamber causes said pumping means to move in one direction within said accumulator chamber until such time as said probe means engages said valve means to relieve the fluid pressure within said pumping chamber, whereby said pumping means moves in the opposite direction to force fluid from said accumulator chamber to said fluid outlet passage.

6. The invention as set forth in claim which includes spring means within said accumulator chamber which expands upon engagement of said probe means with said valve means to cause said pumping means to force said fluid from said accumulator chamber to said fluid outlet passage.

7. In a pumping device for pumping successive pulsed charges of fluid to an associated fluid dispensing mechanism,

a pumping chamber,

valve means controlling the flow of fluid out of said 100 is deenergized, permitting the wax pellet within the housing 100 to cool and subsequently contract.

When the motor 98 is deenerg-ized, the safety spring 110 biases the spring retainer 106 and motor housing 100 toward the right, while at the same time the return spring 5 32 which was compressed during the discharge portion of the operational cycle of the device 10 forces the piston member 24 toward the left, whereby the bolt 140 mounted on the top of the bracket 142 is biased into engagement with the switch 128 resetting the actuating mechanism therewithin and preparing the pumping device 10 for its next successive cycle, as hereinabove described.

It will be seen from the foregoing construction that the pumping device 10 of the present invention provides an extremely simple and compact unit which has very few moving parts and thus may be manufactured at an an extremely low cost. The device 10 will find particular application when used with an associated fluid metering device such as a device for metering successive charges of suitable lubricating fluids to a series of bearing surfaces in production machines and the like. It will be apparent, however, that the pumping device 10 of the present invention is not limited to such use and may be inconporated in any of a number of well known fluid syschamber, tems which use fluid that is delivered in periodic or intera fluid pumping piston having a fluid acumulator chammittent pulsed charges. ber therewithin,

While it will be apparent that the preferred embodisaid piston being movable in one direction within said ment herein illustrated is calculated to fulfill the objects pumping chamber whereby fluid within said pumping above stated, it will be appreciated that the pumping dechamber is forced into said accumulator chamber, vice 10 of the present invention is susceptible to modiand fication, variation and change without departing from means for relieving the fluid pressure within said pumpthe proper scope or fair meaning of the subjoined claim-s. ing chamber whereby said fluid in said accumulator What is claimed is: chamber rapidly surges through said means control- 1. In a fluid pumping device, ling the flow of fluid out of said pumping chamber.

a housing defining a pumping chamber, 8. The invention as set forth in claim 7 wherein said means for relieving the fluid pressure within said pumping chamber is selectively engageable with said means controlling the flow of fluid out of said pumping chamber valve means for selectively communicating fluid to and from said chamber, piston means reciprocable within said chamber,

a fluid accumulator chamber located within said piston means, and

means including said valve means responsive to the movement of said piston means for causing fluid to discharge from said accumulator chamber.

2. The invention as set forth in claim 1 wherein said and wherein the fluid is forced out of said accumulator chamber by an accumulator piston and spring means located within said accumulator chamber.

9. In a fluid pumping device,

a mounting structure,

a housing rigidly secured to said structure and defining means responsive to the movement of said piston means an annular pumping chamber, comprises means on said piston means and engageable fluid passage means formed in said housing and comwith said valve means whereby said valve means is selecmunicating fluid t0 a d f Said Chambfif, tively opened to permit fluid to flow out of said accumuan inlet valve in one of said fluid passage means, lator chamber. an outlet valve in another of said fluid passage means, 3. In a fluid pumping device, an elongated cylindrical pumping piston reciprocable a housing defining a pumping chamber, within said pumping chamber, valve means for selectively communicating fluid to and said pumping piston defining an annular fluid accumufrom said chamber, lator chamber therewithin, first piston means reciprocable within said pumping an accumulator piston reciprocable within said accumuchamber, lator chamber, said piston means defining a fluid accumulator chamber one end of said accumulator chamber being communitherewithin, cable with said pumping chamber whereby an insecond piston means reciprocable within said accumucrease in fluid pressure within said pumping chamber lator chamber, and causes said accumulator piston to move in one direcpower means for moving said first piston means Within tion within said accumulator chamber and a decrease Said P p 'f F Y flllid Within Said in fluid pressure in said pumping chamber causes said -PumPmg chamber W111 flow mm sald accumulator accumulator piston to move in the opposite direction chamljer' Within said accumulator chamber, I 4. The invention as set forth in claim 3 which includes Probe means on said pumping piston and engageable g f engageable l .sald valYe means for whevmg the with said outlet valve to relieve the pressure within u1d pressure within said pumping chamber whereby the h b fluid within said accumulator chamber will be forced Sald pumping c am therefrom by Said Second piston means a motor movably secured relative to said mounting In a fluid Pumping device, structure for biasing said pumping piston in one apumping chamber having a fluid outlet passage, dlrectlon Yvlthln f p m P valve means selectively closing said passage, a return SPTmg for blasmg 831d p p Piston 1n the piston means movable within said chamber, pp direction Within Said P P Chamber, said piston means defining a fluid accumulator chamber, Switch means for deenefgilillg Said motor and movable pumping means Within said accumulator chamber, and therewith relative to said mounting structure, and probe means engageable with said valve means whereby switch tripping means secured to said mounting struc- 7 8 ture and engageable with said switch means to effect References Cited by the Examiner deactuation thereof. UNITED STATES PATENTS 10. The invention as set forth in claim 9 which includes spring means within said accumulator chamber, and where- 1'714260 5/1929 Davls at 222 18 in said spring means is compressed by said accumulator 5 2,599,686 6/1952 Bowmanpiston as the fluid pressure within said pumping chamber FOREIGN PATENTS increases, and wherein expansion of said spring means 122,408 11/1944 Australia causes sa1d accumulator piston to force fluid out of sand accumulator chamber. ROBERT M. WALKER, Primary Examiner. 

1. IN A FLUID PUMPING DEVICE, A HOUSING DEFINING A PUMPING CHAMBER, VALVE MEANS FOR SELECTIVELY COMMUNICATING FLUID TO AND FROM SAID CHAMBER, PISTON MEANS RECIPROCABLE WITHIN SAID CHAMBER, A FLUID ACCUMULATOR CHAMBER LOCATED WITHIN SAID PISTON MEANS, AND 